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```Appendix VL

And   c — 10
From (4) ......... b = -169

Lastly by substituting in (i) (2) or (3),

a =  1377
'"• F lbs< =    *377 - i6QV + ioV2

-1099

which is the equation to the force curve.

P. 4*74. Velocity Curves on Time Base.— The curve
OAB, Fig. 969, represents by its ordinates the actual velocities of
a locomotive, from the moment o of leaving the station till the

4O               Q                           TfME,

Guvrvjes orv Time/ BALS&.       Fig. 969.

expiration of a period of time OE. The scale v shews miles per
hour, and the base scale the minutes from o. A polar distance
OFg of 40 time units is taken, and the sum curve OCD is drawn by
the method at p. 851. The ordinates of this curve, measured by
the scale df will shew the distances travelled from starting, for
d «• i® h true when very small time values are taken at each
Also # » ft, and / is the differential of v regarding £
Therefore the acceleration curve FGH: is obtained as the slope of
the velocity curve, using the polar distance at P! of 8 time units,

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